1. Field of the Invention
The present invention relates liquid crystal display device, particularly relates to a liquid crystal display device that protects an inspection pad for the inspection of a liquid crystal display panel from corrosion and the like.
2. Description of the Related Art
A liquid crystal display device is widely used for various applications from a small-sized cellular phone handset to a large television set because the device has such many characteristics that the device has high display quality, it is thin and light and its power consumption is low.
For example, an active matrix liquid crystal display device is configured by oppositely arranging a thin film transistor (TFT) board and a color filter (CF) board, sticking them via sealing material and sealing liquid crystal between the two boards. In a display area of the TFT board, plural pixel electrodes arrayed in a matrix, plural scanning lines laterally formed and plural signal lines longitudinally formed respectively corresponding to the pixel electrodes and a thin film transistor (TFT) as a switching device which is connected to the corresponding scanning line and the corresponding signal line and which applies predetermined voltage to the corresponding pixel electrode are formed. In addition, a color filter and the like are formed on the CF board.
In the liquid crystal display device, an inspection pad is arranged in a peripheral area of the TFT board so as to check whether disconnection and a short circuit occur in the wiring of the formed scanning lines and signal lines or not and whether the thin film transistor as the switching device is normally operated or not, and inspection is made at a manufacturing stage of the liquid crystal display device.
For example, it is described in Japanese Patent Application Laid-Open Publication No. 2004-310024 that there is included a liquid crystal display panel provided with a gate line, a data line, a switching device connected to the gate line and the data line, a pixel electrode connected to the switching device and an inspection line isolated from the gate line, the data line, the switching device and the pixel electrode for transmitting an inspection signal to the data line; the inspection line includes an inspection pad to which an inspection signal is transmitted from an external device, the inspection pad is arranged in a part in which the external device is touched to the liquid crystal display panel and hereby; since no inspection pad and no inspection line for inspecting the data line and the gate line are formed between data driving IC and gate driving IC and they are formed on driving IC, a degree of the spatial utilization of the liquid crystal display panel is assembly can be enhanced (refer to its abstract).
In the meantime, in a liquid crystal panel according to In-Plane Switching (IPS) and the like, a conductive film is formed on the superficial side of a CF board so as to reduce an effect of electrification charge, and in Japanese Patent Application Laid-Open Publication No. 2010-60696 for example, there is disclosed a liquid crystal display device based upon a liquid crystal display device provided with an electrode board on a surface of which a pixel electrode and a common electrode are arranged, an opposite board arranged opposite to the electrode board and a liquid crystal panel in which liquid crystal material is sealed between the electrode board and the opposite board and having a characteristic that a conductive film formed on the superficial side of the opposite board and wiring for grounding formed on the surface of the electrode board are provided and further, the conductive film and the wiring for grounding are connected via conductive paste (refer to claim 1).
Further, in Japanese Patent Application Laid-Open Publication No. 2006-236870, as a display device having anti-static reinforced structure using a conductive tape, there is disclosed a display device having a characteristic that a circuit board on which electronic parts are mounted, a display element which is connected to the circuit board and which is driven and a conductive tape that electrically connects a GND terminal provided to the circuit board and the electric parts are provided (refer to claim 1).